Abstract
BACKGROUND: Dental caries is a biofilm-related infectious disease with a multifactorial etiology, over five billion inhabitants have affected worldwide due to this disease. OBJECTIVE: Antimicrobial efficacy of a mixed herbal powder extract (MHPE) against cariogenic microorganisms was investigated. MATERIALS AND METHODS: MIC, MBC, kinetics of killing, biofilm disruption and anticaries effect of MHPE were determined. For biofilm disruption, biofilms of Streptococcus mutans, Lactobacillus casei, Actinomyces viscosus and Candida albicans were treated with MHPE for 30 min and attached cells were quantified after staining. For live/dead staining biofilm assay, S. mutans biofilm treated with MHPE for 1min, 5min and 1 h was examined with confocal laser scanning system after live/dead staining. Efficacy was experimented by structural quality using Scanning Electron Microscope (SEM). Anticaries effect was determined by formation of caries-like lesion in continuous flow biofilm model. RESULTS: MHPE exhibited inhibition zones ranging from 12.5 to 24.0 mm. The highest inhibition zone was recorded at concentration of 50 μg/ml. MIC for S. mutans was between 12.23 and 36.7 μg/ml, while the MBC values ranged from 36.7 to 110.65 μg/ml. Inhibitory concentration of MHPE was three fold higher than CHLX. Significant reduction of cell count (49-95%) was observed with increasing time and higher concentration. Percentage biofilm reduction compare with negative control was 96.9% (A. viscosus), 94% (C. albicans), 99.8% (L. casei) and 91.7% (S. mutans). For MHPE-treated biofilm, live/dead staining demonstrated significant (p < 0.05) higher in deceased red fluorescence areas in all kinetics points from 53.6% (1min) to 85% (1h). SEM confirmed the damage in the outer layers of S. mutans. MHPE has components with effective antibacterial activity against caries-inducing microorganisms. CONCLUSION: The anti-adherence and anti-biofilm effect as well as the faster killing activity suggests that MHPE formula has effective antibacterial activity and could be a useful source of anti-cariogenic agents in near future.